The present invention relates to a disc brake according to the preamble of claim 1. The invention also relates to a brake pad set for a disc brake.
Such disc brakes are used in commercial vehicles in particular and are often provided with pneumatic actuation. One embodiment of the brake caliper of such a disc brake is designed as a disc caliper and is used in a tight installation space, for example.
The brake caliper is usually connected to the so-called brake carrier by two bearing spars, which are designed as fixed bearings and loose bearings. The brake pads of the disc brakes are guided displaceably in the brake carrier and are held in a spring-loaded connection by pad retainer brackets in pad slots in the brake carrier.
In the case of disc brakes, in particular disc brakes having only one force-introducing element, uneven wear may occur on the brake pads due to the design. The brake pads may develop wear that is not parallel relative to a plane through their pad carrier plates in the radial direction, on the one hand, but also in the circumferential direction. This is referred to as radial wear and tangential wear, respectively.
One example of a spring-loaded pad retaining bracket is described in german patent document no. DE 20 2008 013 446 U1.
Brake pad retainer systems are disclosed in International patent document no. WO 2013/143993 A1, German patent document no. DE 10 2012 002 734 A1, and U.S. Pat. No. 8,540,061 B1.
Against the background of these approaches, there is still a constant demand for brakes and brake components that have a longer lifetime with a reduced cost at the same time.
An object of this invention is therefore to create an improved disc brake.
Another object is to provide an improved brake pad set for a disc brake.
The invention achieves these and other objects, by a disc brake for a vehicle, in particular for a commercial vehicle, which includes a brake disc having an axis of rotation, at least one brake pad on the clamping side and one brake pad on the rear side, a brake carrier which holds at least two brake pads in a respective pad slot, the at least one brake pad on the clamping side being held in a form-fitting manner in the respective pad slot, a brake caliper designed as a disc caliper and extends beyond the brake disc, wherein the brake pad on the clamping side is provided with at least one pad retaining spring supported at least on a brake carrier horn of the pad slot of the brake carrier and exerts a tensile force on the brake pad acting radially outward.
The tensile force acting radially outward makes it possible for the brake pad to be pulled into its form-fitting retainer, thus advantageously permitting a reduction in tangential wear.
It is possible to create the tensile force through an advantageously simple arrangement with at least one pad retaining spring, which is supported on a brake carrier horn of the pad slot after the brake pad has been installed.
In addition, there is the advantage that the pad retaining spring is no longer supported on a pad retainer bracket and the brake pad with the pad rear plate can no longer strike the pad retaining spring. Therefore, damage to the pad retaining spring can be reduced and its lifetime can be increased.
In one embodiment, the at least one brake pad on the clamping side is engaged in a form-fitting manner with a pad rear plate in the pad slot of the brake carrier with contours of brake carrier horns. This advantageously makes it possible to secure the brake pad on the clamping side in both radial directions with respect to the axis of rotation of the brake disc.
In another embodiment, it is provided that the contours of the brake carrier horns correspond to the contours of the pad rear plate, wherein undercut surfaces of the contours of the brake carrier horns are each engaged, free of play, with undercut surfaces of protrusions on the pad rear plate. It is therefore possible to further improve the reduction in wear.
In another embodiment, the at least one pad retaining spring is mounted on the pad rear plate. This creates a compact brake pad.
The at least one pad retaining spring may be mounted on the top side of the pad rear plate, which permits space savings.
Yet another embodiment provides that the at least one pad retaining spring comprises a central section, arms, pressure sections and transitional sections, wherein the central section is mounted on the top side of the pad rear plate, wherein the transitional sections sit on the top side of the pad rear plate, and the pressure sections protrude laterally away from the pad rear plate, each on one end of the top side of the pad rear plate. Thus, a simple and effective prestressing of the pad retaining spring can be created. The pad retaining spring may be a flat spring steel, for example, from which it is produced as a punched bending part.
In one alternative embodiment, the at least one pad retaining spring has a central section, arms, pressure sections and intermediate sections, wherein the central section is mounted on the pad rear plate with at least one mounting element, wherein the pressure sections protrude laterally from the pad rear plate, one section on each end of the top side of the pad rear plate. This advantageously makes it possible to use available fastening elements with only minor changes or without any changes at all.
To do so, the at least one fastening element may be designed like a clamp and may have a cross section which extends through an opening in the pad rear plate in the installed state of the pad retaining spring, such that the pad retaining spring is arranged between the at least one fastening element and the top side of the pad rear plate. This is advantageous because the pad retaining spring is in this way in a captive mount on the pad rear plate of the brake pad. Another advantage is the play in the central part of the pad retaining spring between the fastening element and the pad rear plate, so that a uniform load on the pad retaining spring can be achieved.
In another embodiment, the pad retaining spring has at least one slot through which a section of the at least one fastening element extends. Thus, for example, punching tools that are present may be used for slots in pad retaining springs. Furthermore, a captive mount is possible between the pad retaining spring and the fastening element.
According to yet another embodiment, the pad retaining spring has at least one additional slot, through which a guide protrusion on the pad rear plate extends. In this way, the pad retaining spring on the top side of the pad rear plate can advantageously be held, so that it is centered on the top side and is guided in its possible longitudinal movements, so that contacting of the pressure sections with the brake carrier horns remains ensured.
When at least one of the pressure sections is supported on the at least one brake carrier horn of the pad slot of the brake carrier, an advantageously simple tensile force is created on the brake pad and no additional measures are required on the brake carrier.
In one alternative embodiment, the at least one pad retaining spring is mounted on a top side of the pad rear plate by means of at least one spring retainer. This permits advantageous weight savings.
Another embodiment provides that the at least one spring retainer has at least one retaining element, wherein the at least one pad retaining spring is arranged between the at least one retaining element and the top side of the pad rear plate and is held prestressed there. This yields a simple means of creating prestress.
In yet another embodiment, the at least one pad retaining spring comprises at least one central section, transitional sections, at least one pressure section and at least one bearing section.
Another embodiment provides that the at least one bearing section sits on the top side of the pad rear plate, and the at least one pressure section protrudes laterally from the pad rear plate on one end of the top side of the pad rear plate. This yields an advantageously compact design.
For an advantageously simple means of creating a tensile force, which acts on the brake pad, the at least one pressure section is supported on the at least one brake carrier horn of the pad slot of the brake carrier.
In another embodiment, the at least one retaining element is designed as a roller, in particular a cable roller. Such a roller design has the advantage of a lateral guidance of the pad retaining spring.
In a preferred embodiment, it is provided that the at least one pad retaining spring is produced from a spring wire. The pad retaining spring is therefore simple to manufacture.
Another preferred embodiment provides that such a pad retaining spring is arranged on each end of the top side of the pad rear plate. This yields an improved tensile force creation.
In one alternative embodiment, the at least one pad retaining spring is held and guided on the pad rear plate. This yields a simple mounting of the pad retaining spring on the pad rear plate.
In one embodiment, it is also provided that the least one pad retaining spring comprises a central section, arms and pressure sections, wherein the central section with a retaining section and connecting sections is in interaction with a fastening section of the pad rear plate, such that the fastening section forms, on the one hand, a fixation of the central section against lateral slipping of the central section and thus the pad retaining spring connected to it in the direction of a friction lining and, on the other hand, permits further fixation of the central section and thus of the pad retaining spring connected to it in the radial direction away from the top side of the pad rear plate, so that it points away from them. With the help of these fixations, it may be made possible for the pad retaining spring of the brake pad to be pulled radially upward and for lateral slipping to be preventable at the same time.
Therefore, the fastening section with a lug may form the additional fixation of the central section and thus of the pad retaining spring connected to it in the radial direction. This is a simple design without any additional components.
It may be provided here that the fastening section protrudes away from the top side of the pad rear plate, the lug being mounted on an upper edge of the fastening section and protruding as a protrusion toward an actuating side of the pad rear plate. This is also easily made possible without additional components.
It is advantageously simple if the lug is created by producing a contour, for example, by machining a contact surface beneath the lug on the fastening section.
In one embodiment, the central section of the pad retaining spring is in contact with the retaining surface along a side edge of the retaining section and along side edges of connecting sections, wherein the side edges and top sides of the connecting sections are in contact with the bottom and/or ends of the bottom side of the lug. An advantageously simple insertion of the pad retaining spring into the contour and/or beneath the lug is possible in this way.
If the pad retaining spring has at least one slot, through which a guide protrusion on the pad rear plate extends, then the pad retaining spring is advantageously additionally secured against twisting about a vertical axis as well as about its longitudinal axis.
In another embodiment, the pad retaining spring may have a recess and may thus have a reduction in its width between the slots, at least of the central section. This yields a compact design.
If the pressure sections protrude laterally away from the pad rear plate on each end of the top side of the pad rear plate, this yields, on the one hand, a compact design and, on the other hand, a simplified assembly.
It is advantageous here that at least one of the pressure sections is supported on the at least one brake carrier horn of the pad slot of the brake carrier, thus creating a tensile force, which acts on the brake pad.
In another alternative, it is provided that the at least one pad retaining spring is held in a form-fitting manner in the pad rear plate. This advantageously permits retention and introduction of a tensile force.
The at least one pad retaining spring here has a central section with a retaining section and two connecting sections, two arms and two pressure sections, wherein the retaining section is held in a form-fitting manner in a retaining opening in the pad rear plate and the two connecting sections are held in a slot in the pad rear plate. This is advantageous because no additional retainers are necessary, on the one hand, and, on the other hand, simple installation of the pad retaining spring by simple insertion is possible.
In one embodiment, the retaining section has a circular cross section with a central axis running parallel to an axis of rotation of the brake disc and designed like a pipe clamp with two connecting sections. This is simple to manufacture, for example, when the pad retaining spring is manufactured as a punched/bending part.
Another embodiment provides that the retaining opening is designed as a through-opening or as a blind hole with a circular cross section or with a different cross section, such as, for example, a triangular or polygonal cross section, wherein the retaining opening is connected to the top side through the slot and is at a distance from the top side of a fastening section in the radial direction. This yields a simple and compact design without any additional parts.
In another embodiment, the fastening section protrudes away from the top side of the pad rear plate and is divided by the slot into two subsections with the respective top side. In this way the central section with the pad retaining spring is held easily and securely on the pad rear plate.
If the pad retaining spring has a constant width over the total length of the pad rear plate, wherein the pad retaining spring protrudes beyond the pad rear plate in the direction of a friction lining, then a simplified assembly is possible because the pressure sections of the pad retaining spring come in contact first with the brake carrier horn(s) due to the protrusion of the pad retaining spring when the brake pad is installed. Pressing on the brake pad then creates the prestress on the pad retaining spring, so that the brake pad is then displaced into the brake carrier.
If the pad retaining spring has at least one slot through which a guide protrusion on the pad rear plate extends, an advantageously simple guidance and fixation of the pad retaining spring on the pad rear plate are made possible.
If the pressure sections each protrude laterally away from the pad rear plate on one end of the top side of the pad rear plate, this also yields a compact design in this embodiment, on the one hand, and simplified assembly, on the other hand.
It is advantageous here that at least one of the pressure sections is supported on the at least one brake carrier horn of the pad slot of the brake carrier, thus creating a tensile force acting on the brake pad.
Yet another alternative embodiment provides that each spring retainer has a plate-shaped protrusion, which extends away from a top side of the pad rear plate and to which the at least one pad retaining spring is fastened. Weight can be saved in this way and a compact design is made possible.
In one embodiment, the at least one pad retaining spring is designed in the form of a hood, which results in easy assembly.
In this regard, the at least one pad retaining spring has a base plate, two fastening straps and a spring arm, each with a pressure section, so that the at least one pad retaining spring is mounted with the fastening straps on the respective protrusion. The pad retaining spring may advantageously be produced easily as a punched/bending part.
It is advantageous if the at least one pad retaining spring is mounted in a form-fitting manner on the respective protrusion because simple assembly and positioning on the protrusion are possible in this way.
If the at least one pad retaining spring is mounted securely and in a form-fitting manner on the respective protrusion, this yields the advantage of a safety against loss. Such a form-fitting and secure mounting can be established by riveting, bolting and the like, for example.
In another embodiment, the spring arm of the at least one pad retaining spring is fastened to the base plate by a curved connecting section. This yields the advantage of creating an additional spring force.
In addition, the curved connecting section can communicate with the shape of a contact surface of the protrusion, so that an advantageous and compact support of the connecting section in the uninstalled state of the brake pad is possible.
In yet another embodiment variant, the at least one pad retaining spring may have at least one supporting section, which is mounted on the base plate opposite the spring arm and has on its bottom side at least one supporting section, which is supported on the top side of the pad rear plate. This makes it possible to prevent a rotational movement of the pad retaining spring about its mount on the protrusion.
In yet another embodiment, the at least one pad retaining spring may be provided with at least one slot. This yields the advantage that the different spring forces required for different application cases can be obtained. This may also take place due to the fact that the at least one pad retaining spring is provided with at least one reinforcing bead and/or at least one reinforcing rib. The reinforcing bead and/or reinforcing rib may be used alone or in combination with the at least one slot.
The at least one pressure section protrudes laterally away from the pad rear plate at one end of the top side of the pad rear plate and thus permits a compact design.
It is advantageous here that the at least one pressure section is supported on the at least one brake carrier horn of the pad slot of the brake carrier, thereby creating a tensile force acting on the brake pad.
In a preferred embodiment, it is provided that at least one pad retaining spring is arranged on each end of the top side of the pad rear plate.
A brake pad set for a disc brake described above for a vehicle, in particular for a commercial vehicle, includes at least one brake pad on the clamping side and at least one brake pad on the rear end. The brake pad on the clamping side has at least one pad retaining spring with at least one pressure section, wherein the at least one pressure section protrudes laterally beneath one end of the top side of a pad rear plate of the brake pad on the clamping side.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.